EXAM #2: ENDOCRINE PANCREAS ANATOMY

Question 1

What are pancreatic islets embryologically derived from?

Answer 1

Endoderm

Question 2

What hormone is secreted by Beta cells in the pancreas?

Answer 2

Insulin

Question 3

What hormone is secreted by Alpha cells in the pancreas?

Answer 3

Glucagon

Question 4

What hormone is secreted by Delta cells in the pancreas?

Answer 4

Somatostatin

Question 5

What is contained in an immature secretory vesicle of the beta cells? What happens in this vesicle?

Answer 5

Proinsulin, which is cleaved into Insulin and Protein C

Question 6

How does Clathrin differentiate between an immature vesicle and mature vesicle in the Beta cell?

Answer 6

Immature= clathrin coated 
Mature= no clathrin

Question 7

Which has a longer half-life, insulin or protein c?

Answer 7

Protein C

Question 8

Is GLUT-2 dependent or independent of insulin?

Answer 8

Independent

Question 9

What is the mechanism of insulin release from the beta cells?

Answer 9

1) Glucose in via GLUT-2
2) Glycolysis increases ATP
3) ATP binds K+ sensitive channel, inactivating it and leading to membrane depolarized (Sulfonylurea Receptor)
3) Ca++ enters voltage gated channels
4) Insulin is released via exocytosis

Question 10

What drugs target the K+ channel necessary for insulin release?

Answer 10

Sulfonylurea class drugs i.e.

• Gliclazide
• Glimepiride

Question 11

What transporter is necessary for glucose entry in target cells?

Answer 11

GLUT-4

Question 12

Is GLUT-4 dependent or independent of insulin?

Answer 12

Dependent

Question 13

What does insulin do to target cells?

Answer 13

• Causes insertion of GLUT-4 transporters into membrane

- Glucose enters the cell

Question 14

What is the embryologic origin of the adrenal cortex?

Answer 14

Mesoderm

Question 15

What is the embryologic origin of the adrenal medulla?

Answer 15

Neural crest cells

Question 16

What is required for the differentiation of neural crest cells to chromaffin cells in the adrenal medulla?

Answer 16

Cortisol

Question 17

What is the mnemonic to remember the parents vessels of the suprarenal arteries?

Answer 17

IPAR

Inferior phrenic= superior suprarenal a.
Aorta= middle suprarenal a.
Renal= inferior suprarenal a.

Question 18

What is the origin of the cortical and medullary arteries?

Answer 18

Supracapsular arterial plexus (plexus under the capsule from the suprarenal a)

Question 19

What capillaries receives the hormones from the adrenal cortex?

Answer 19

Sinusoidal capillaries in the cortex

Question 20

Where does the right suprarenal vein empty?

Answer 20

IVC

Question 21

Where does the left suprarenal vein empty?

Answer 21

Left renal vein

Question 22

What are the three zones of the adrenal cortex?

Answer 22

GFR:

Glomerulosa
Facsiculata
Reticularis

Question 23

What is the mnemonic to remember the hormones released from the zones of the adrenal cortex?

Answer 23

Salt, sugar, sex

Aldosterone= G
Cortisol= F
Androgens= R

Question 24

Histologically, what do you NOT see in the adrenal cortex would be expected b/c of the glands high output of secretory products?

Answer 24

Secretory vesicles; steroid hormones diffuse across membrane unlike peptide hormones

Question 25

ACTH has a stimulatory effect on which two parts of the adrenal cortex?

Answer 25

Fasiculata and reticularis, NOT Glomerulosa

Question 26

What is the expected gross finding in the setting of ACTH excess i.e. Cushing's?

Answer 26

Cortical hypertrophy contributed by Fasiculata and Reticularis ONLY

Question 27

What hormone has a major inhibitory effect on ACTH and cortisol secretion?

Answer 27

Glucocorticoids

Question 28

What segmental levels of the SNS innervate the adrenal medulla?

Answer 28

T8-L1

Question 29

Catecholamines are derived from what amino acid?

Answer 29

Tyrosine

Question 30

List the steps in catecholamine synthesis?

Answer 30

1) Tyrosine 2) DOPA 3) Dopamine 4) NE 5) Epinephrine

Question 31

What enzyme converts NE to Epi? What hormone activates this enzyme?

Answer 31

Phenylethanolamine-N-methyltransferase, which requires cortisol

Question 32

In catecholamine synthesis, which is the only product that is NOT made in the cytoplasm?

Answer 32

NE *Dopamine to NE enzymatic step occurs in the secretory vesicle

Question 33

When catecholamine synthesis increases, what binding protein also increases?

Answer 33

Chromogranin

Question 34

What is the Organ of Zuckerkandl?

Answer 34

Ectopic adrenal-medulla tissue in the region of the aortic bifurcation

Question 35

A tumor of the Organ of Zuckerkandl i.e. a pheochromocytoma, is expected to increase the output of what?

Answer 35

Norepinehprine *Without cortisol from the adrenal cortex, cannot convert NE to Epi

Question 36

In Congenital Adrenal Hyperplasia, with the enzyme that produces cortisol deficient, describe the sequence of events that results in ambiguous genitalia in the female?

Answer 36

1) Decreased cortisol and shunting down the other pathways 2) Adrogens increased 3) Decreased cortisol leads to increased ACTH causing positive feedback and increased androgens *Leads to ambiguious in the female patient